The invention relates to a process for the assembling of a gear unit, in particular one with the features from the generic term of claim 1.
Gear units are known in a large number of executions. These can be executed as
a) mechanical gear units
b) hydrodynamic-mechanical compound gear units.
Hydrodynamic-mechanical compound gear units are known, for example, from the following publications;
Buksch, M: ZF-five gear automatic gear systems for passenger automobiles, VDI report 878 (1991@
Nitescu, G.: Four-gear planetary gear for passenger motor vehicles with the hydrodynamic torque converter in the power branching, Automobilindustrie (1985) 5, pages 597-601
Klement, W.: The development of the DIWA gear system, Verkehr und Technik (1987) 7, pages 301-303
The gear construction units which have either only purely mechanical transmission components or else consist of a combination of a hydrodynamic converter or of a hydrodynamic coupling with a downstream mechanical gear set have as a rule a housing which is adapted, in respect to its inner contour, to the formation and tying of the individual gear elements onto the housing, and have, as a rule, inner insets which undesirably reduce the inside diameter. For example, one gear system obtainable on the market uses a threading on six rods or bars distributed at equal intervals about the circumference of the inner contour, with the aim of a very simple assembling of the components or gear elements. The individual rods ensure the gear elements against twisting in circumferential direction. The arrangement of the six bars, as viewed in circumferential direction of the gear unit, with constant spacing between two adjacent bars, as well as the number of these bars, however, considerably reduce the inside diameter of the gear since essentially the upper has in installation position reduce the construction height and therewith the possibly usable planetary diameter. The gear interior space, with respect to the present outside dimensions of the gear, cannot be used optimally for the gear elements. From the publication U.S. Pat. No. 3,475,992 there is known an execution of a compound gear component, in which individual elements, for example the pump execution, the input shaft, are preassembled outside of the gear housing and then installed from the left into the housing. The remaining gear components, such as distributor gear, bridging coupling, planetary wheel gear are then introduced individually into the housing from the right side of the housing. Some of the elements, such as braking elements, couplings, are borne there on guide elements, and these guide elements in correspondence to the introduction from the left or the right side are executed in several parts and corresponding partitions are borne between them. Also, the guide elements are supported on the end zones of the housing, i.e. on the housing cover. This means that with corresponding bearing of actuating elements axial forces are transferrable onto the housing cover, for which reason the gear component cannot be separately tested in advance without the housing cover.
Underlying the invention, therefore, is the problem of creating a process for the assembling of a gear component in which, besides a simple assembling, it is also ensured that with external prescribed installation dimensions there can be achieved as great as possible an inside diameter of the gear component. Further, emphasis is to be placed on a reduction of the constructive and manufacturing technical expenditure as well as on a minimizing of the requisite number of parts.
The solution of the problem according to the invention is characterized by the features of claim 1. Advantageous developments are described in the subclaims.
The gear component, which comprises a gear housing and a substantially cylindrical interior space, has at least two bar-form elements for the tying-on of gear elements either in radial direction or in circumferential direction. The bar-form guide elements extend there essentially over a range in which the gear elements provided for the typing-on are arranged. The bar-form guide elements are allocated to the cylindrical interior space and arranged in a zone outside of this, the allocation taking place in such manner that the bar-form guide elements are provided outside of a zone which, as viewed in installation position of the gear system, corresponds to the greatest dimension of the interior space of the gear unit, in height direction. According to the invention the individual gear elements are threaded successively from one housing side onto the guide elements and brought into their installation position in the gear housing.
Preferably none of the guide elements is arranged in installation position above the greatest dimensioning in height direction of the interior space in the gear housing, but in the formerly material-intensive zones of the gear housing with substantial quadrilateral gear exterior contour with cylindrical inner space.
With the solution according to the invention accordingly the inside diameter or the inside contour of the gear housing can be made appreciably larger with installation measurements that remain the same for the gear unit and (sc. the space needed for) the assembling, as well as the interchangeability of the individual gear elements in axial direction can be reduced. Through the guidance of the bar-form guide elements in the recesses that are connected with the cylindrical interior space the cylindrical inner space can be completely used by the gear elements in respect to their radial extent. For example with the execution of the gear elements as a lamellar coupling, the area describable by the cross section surface of the interior space can be used completely as a friction surface. Since the bar-form guide elements do not collide with the interior space, also the other rotating gear elements, for example planetary wheel sets, can be designed in such manner that the entire interior space is completely utilized in radial direction. This leads to the result that through the diameter increase with equal construction length a greater torque can be transmitted. It is possible to dispense with additional interior insets for the bearing, which reduce the diameter of the interior space. The suspension on the bar-form guide elements prevents twisting of the individual gear elements in circumferential direction.
Compulsorily required for the guidance are only two bar-form elements; there are required at most four and preferably four bar-form guide elements are used. The arrangement occurs in this case, as viewed in the cross section of the gear housing, in the comer zones, which (cross section) is describable by the section size between the cylindrical interior space and a theoretically generatable quadrilateral, preferably the quadrate Qtheoretic with a side dimension greater or equal to the diameter of the interior space, the theoretically generatable quadrate Qtheoretic and the interior space having identical axes of symmetry. In this case especially with a rectangular housing with cylindrical interior space the material-intensive comer zones are used for the reception of the guide elements. The guide elements there are conducted in recesses which are connected with the cylindrical interior space. Preferably, however, the arrangement of the guide elements always occurs symmetrically. This offers the advantage that the manufacturing expenditure for the gear elements and the gear housing can be minimized as can also the assembling expenditure, since it is not necessary to heed how the individual recesses or the passage openings on the gear elements must be formed for the reception of the guide elements. Also the housing base body with the recesses can be manufactured independently from the later actual installation position.
As gear elements there can be regarded, for example, braking arrangements in the form of lamellar brakes, partitions, actuating elements for braking or coupling arrangements, for example in the form of pistons, lamellae carriers or the like.
The bar-form elements preferably have an equal or constant diameter over their axial extent. This offers the advantage that the assembling can occur independently from the installation direction of the bar-form elements. Also thinkable, however, depending on the formation of the total gear unit, is the use of bar-form elements with a different diameter over the axial extent. In this, however, as a rule there will occur an assembling from two sides.
By bar-form elements there are meant there guide elements the profile of which is constructed as a solid or hollow profile, or a combination of the two.
The guide elements, further, according to their tying-on, can function as a shaft or as an axle.
It is also conceivable, for example, to execute a guide Element as a hollow axle, which encloses, for example, a shaft for the drive of accessory aggregates, or an axle.
The cross section of the bar-form guide elements is preferably circular. Also thinkable, however, are executions with quadrilateral cross section or arbitrary cross section.
In regard to the bearing of the bar-form guide elements the following variants can be used:
a) Bearing on the housing in housing wall projections
b) Bearing in partitions which are threaded onto the guide elements
c) Suspended bearing on a wall projection or a partition, for example on the face sides of the gear unit, for example over covers
d) Bearing over wall projections (lugs)
e) Combination of a)-d)
The gear unit can be constructed as a purely mechanical gear unit. In this case each bar-form guide element extends preferably over the entire axial extent of the gear unit. In the execution of the gear unit as a hydrodynamic-mechanical compound gear system, the bar-form guide elements is provided at least with an axial length which corresponds to the axial extent of the mechanical gear part with respect to the total gear component. It is always required, however, that the axial extent of the guide elements corresponds to the axial extent of the gear elements supported on these.
A further possibility for the bearing of the bar-form elements lies in using the housing cover. In the especially preferred forms of execution, however, this possibility is dispensed with.
In an especially preferred gear component also devices are led for the resetting of actuating elements of the lamellar braking and/or coupling arrangements, and through the bar-form guide elements. Between the two friction surface-carrying elements which are indirectly couplable with one another over a friction surface-carrying intermediate element, there is provided at least one spring storage arrangement which is likewise led over the bar-form guide element and is laid out in such manner that on generation of the friction closure between the friction surface-carrying elements and the intermediate element the spring storage arrangement is pretensionable. By friction surface-carrying elements there are meant there the elements which are couplable with one another over an intermediate element. In each case a friction surface-carrying element and a friction surface-carrying intermediate element form, on pressing-on, a friction surface pair. By friction surface there is meant there the surface or the surface-zone which is involved in the friction closure. The friction surface there can be a component of the friction surface-carrying element or of the intermediate element, or be allocated to this as a separate element, for example in the form of a coating. The friction surface or the surface zones functioning as friction surface of a friction surface-carrying element or of an intermediate element can be generated, further, by coating or surface treatment. The function of the friction surface-carrying elements can be taken over there both from outer and also from the inner lamellae. By reason of the effect of the spring storage unit between the individual friction surface-carrying elements, the relaxation of the actuating element in each case an oppositely directed force, acts on the friction surface-carrying elements, so that a rapid separation with complete releasing of the friction closure becomes possible. The spring storage arrangement acts therefore indirectly on the actuating element, over the friction surface-carrying elements. The actuating element itself can be executed, for example, as a piston, which preferably can be acted upon hydraulically or pneumatically. This possibility of arranging the spring storage units between the friction surface-carrying elements offers the advantage that the dimensions of the friction surface-carrying elements in radial direction are no longer dependent on the size of the inner dimensions of the gear housing, with account taken of the requisite construction space for the device for the at least indirect resetting of actuating elements. The arrangement of spring storage units between the friction surface carrying elements connectable with one another by friction closure over an intermediate element, offers also the advantage of a space-saving execution of the resetting device, especially of the piston of a cylinder/piston unit in axial direction, which again affects the gear length in use of the braking arrangements in lamellar construction in a gear. In respect to the arrangement of the spring units between the friction surface-carrying elements, a large number of possibilities are thinkable:
a) Arrangement of spring units between each of the two adjacent friction surface-carrying elements;
b) Arrangement of the spring units in force flow direction between the friction surface-carrying elements in the region of the force introduction (in the region of the in each case outside-lying friction surface-carrying elements with respect to the installation position of the braking arrangement in a gear unit);
c) Arrangement of the spring unit between two friction surface-carrying elements adjacent to one another in respect to the axial extent of the braking arrangement in the middle zone of this;
d) Arrangement according to b) in combination with c);
e) Arrangement of spring units in correspondence to the possibilities described in a) to d) in combination.
The possibilities described in b) to e) deal with executions in which a spring unit is not arranged between each friction surface pair bringable into engagement with one another. The force interruption can occur there at any point of the braking arrangements.
As spring storage units there are preferably used spring elements which have a characteristic curve with an essentially constant force flow over a certain spring path. Preferably, therefore, cup springs are used. The execution of the spring units as a shaft spring ring is likewise conceivable. The actuation arrangements used can be executed as cylinder/piston arrangements which can be acted upon hydraulically or pneumatically. In correspondence to the arrangement of the piston for the resetting device over the friction surface-carrying elements, there are especially effective lamellae on the piston, either in the zone of the piston surface or outside of the piston surface. In respect to the formation of the piston there are distinguished executions with
a) one piston
b) plurality of pistons.
The appertaining cylinders can be formed there by a cylinder-carrying element or a plurality of cylinder-carrying elements. This possibility of piston resetting offers the advantage of a minimal construction space requirement in a radial as well as in an axial direction. In combination with the solution according@ to the invention there is given the possibility of creating a gear component with the possibility of high torque transfer with a constant-remaining structural height or a reduced structural height.